Intracranial pressure ( ICP) monitoring has been strongly recommended in selected patients with a severe traumatic brain injury (TBI) with the rationale of early identification and treatment of intracranial hypertension to maintain adequate cerebral blood flow and oxygenation. This recommendation was not based on Level 1 evidence, but derived from the retrospective and limited prospective observational studies. The recommendation on ICP monitoring for severe TBI dates from the first edition of the Brain Trauma Foundation (BTF) guidelines. There was no difference in the recommendation between the first and second edition of the BTF guidelines. Both editions mentioned that there is a lack of standard for recommendation on ICP monitoring.[1] However, ICP monitoring is appropriate in patients with a severe TBI with an abnormal computed tomography (CT) scan.[1] ICP monitoring is not routinely indicated in patients with mild or moderate TBI. However, a physician may choose to monitor ICP with traumatic mass lesion.[1] The third edition of the BTF guidelines was more prescriptive.[2] Although there was a lack of Level 1 evidence supporting routine monitoring of ICP, based on Level 2 evidence, the BTF recommended that “ICP should be monitored in all patients with severe TBI with an abnormal CT scan.” The Level 3 recommendation was “ICP monitoring is indicated in patients with a severe TBI with a normal CT scan if ≥2 of the following: age >40 years, unilateral or bilateral motor posturing, and systolic blood pressure <90 mmHg.”[2] After the publication of a randomized trial of ICP monitoring, the latest edition of the BTF guidelines mentioned that there was insufficient evidence to support recommendation for ICP monitoring. However, the management of severe TBI patients using information from ICP monitoring is recommended to reduce in-hospital and 2-week postinjury mortality.[3] The BTF guidelines are US based, and not practiced universally.

In the Japan Neurotrauma Data Bank analysis of 1091 cases from 2009 to 2011, it was found that the rate of ICP monitoring as per the Japanese guidelines for the management of severe TBI was 28%, and earlier it was 55%.[4] The indications for ICP monitoring were not based on the guidelines, but the ICP monitored was performed in younger patients, diffuse injury III-IV, evacuated mass lesions, perimesencephalic cistern compression, and midline shift of ≥5 mm. The patients in ICP-monitoring group received more hyperventilation, hyperosmolar diuretics, sedatives, anticonvulsants, surgical treatment, and temperature management. Besides maximum ICP value, age, Glasgow Coma Scale (GCS) score, papillary abnormalities, and perimesencephalic cisterns were significant determinants of outcome. The mortality rate was 35.2% in ICP-monitoring group and 45% in nonmonitored group. The favorable outcome rates for these two groups were 29.2% and 30%, respectively.[4] The Japan Neurotrauma Data Bank analysis showed that the rate of ICP monitoring in the treatment of severe TBI came down. Therapies were performed aggressively in the ICP-monitoring group. However, no increase in the favorable outcome rate was found with ICP monitoring.[4]

In an Indian study analyzing the adherence of BTF guidelines in a single center, ICP monitors were placed in 126 (63%) of 200 patients. Patients with ICP monitor placement experienced lower in-hospital mortality (adjusted relative risk: 0.50 [0.29, 0.87]) than patients without ICP monitoring. However, there was no benefit at 3, 6, and 12 months. The absence of cerebral edema and intraventricular hemorrhage was associated with reduced unfavorable outcomes.[5]

The Benchmark Evidence from South American Trials: Treatment of Intracranial Pressure Trial (BEST-TRIP) compared the two treatment protocols: clinical monitoring including imaging and ICP monitoring in addition to the clinical monitoring.[6] There was no difference in early and late mortality rates between the two groups (P = 0.19 and 0.60, respectively).[6] This trial was performed by North Americans, and the results were not acceptable to them; hence, they released a consensus-based interpretation of the BEST-TRIP.[7] The strongest statement was on lack of generalizability of the results. The maximum burden of neurotrauma is in developing countries; hence, these results are definitely generalizable globally.

Even in America, the ICP monitoring is not practiced uniformly. In the American College of Surgeons (ACS)-Trauma Quality Improvement Program (TQIP) database queried for a 2-year time range (2013–2014) for the patients who met the criteria for ICP monitoring, only 10.8% of patients underwent ICP monitoring in Level 1 centers.[8] Logistic regression was used to compare the outcome. The ICP monitoring placement was found to be an independent risk factor for mortality, mechanical ventilation, intensive care unit (ICU) length of stay, systemic complications, and decreased functional independence at discharge.[8]

In the present study, the authors investigated the association of ICP monitoring and clinical outcome in patients with an isolated severe blunt TBI from the ACS-TQIP database during 2014.[9] The ICP was monitored in 18.3% of patients who met the criteria for ICP monitoring. Unlike the previous TQIP database analysis that used logistic regression, the current study used propensity score matching, which is a superior technique for comparing two cohorts.[9] A propensity score is the probability that a unit with certain characteristics will be assigned to the intervention group (as opposed to the control group). The scores can be used to reduce or eliminate selection bias in observational studies by balancing covariates between intervention and control groups. This method approximates a random experiment, eliminating many of the problems that come with observational data analysis. The propensity score matching mimics some of the particular characteristics of a randomized controlled trial.[10] The current study showed that the ICP monitoring was associated with an increased risk of systemic complications such as deep venous thrombosis, acute respiratory distress syndrome, and sepsis. The ICP-monitored group had significantly increased length of stay both in ICU and hospital. The ICP-monitored group had an increased mortality risk with odds ratio of 1.6 (95% confidence interval: 1.1–2.5, P = 0.038).[9]

Based on the previous observation and current study, it can be concluded that ICP monitoring cannot be considered as a standard for the management of severe TBI. The question should not be whether to monitor ICP, but in whom to monitor ICP. Unless a lot of studies that globally replicate the results of studies showing benefit of ICP monitoring in improving outcomes in severe TBI, the ICP monitoring will not be incorporated in the management of severe TBI protocols, particularly in resource-limited settings.